For the electric testing of microelectronic components, test heads based on the buckling beam concept, as described in European patents 0 165 331 and 0 283 545 are increasingly employed. Such contact probe arrangements comprise, inter alia, a first perforated plate pack, in which the contact probes are guided so as to be laterally deformable, and a second perforated plate pack, on or in which the contact probes are attached.
The fastening of the contact probes through embedding or adhesive bonding is no longer possible with very densely arranged contact probes. FIG. 1a shows the problems which arise in embedding or bonding, particularly with those contact probes which are covered with an insulating layer 6. Layer 8 is, for example, a copper layer. This insulating layer surrounding the contact probes outside the second perforated plate pack mostly ends directly at the guide holes intended for the contact probes in the second perforated plate pack and there forms a blockage. No adhesive or embedding material can flow into the guidance hole when it is blocked in this way.
A suitable low viscosity adhesive for a lasting and heat-resistant adhesive bond between the partly insulated contact probes and the second perforated plate pack is e.g. EPOTEK 353-ND. As shown in FIG. 1b, such adhesives rise to a height of 15 mm on the contact probes, which is unacceptable.
Highly viscous adhesives or thixotropic adhesives such as EPOTEK 353-ND/T, of course, climb up the contact probes only negligibly, to a height of approximately 2 mm but, on the other hand, do not penetrate sufficiently deeply into the guidance holes of the perforated plate pack, so that the contact probes have an inadequate fastening action. This problem is shown in FIG. 1c.
Both EPOTEK 353ND and EPOTEK 353ND-T are two component epoxy adhesives available from Epoxy Technology Inc., 14 Fortune Drive, Billerica, Mass. 01821. Epoxy 353ND has a viscosity of 2000 CPS, a TCE (thermal coefficient of expansion) of 54.times.10.sup.-6 /K and a lap shear strength of 1500 PSI while EPOTEK 353ND-T has a viscosity of 43000 CPS, a TCE of 43.times.10.sup.-6 /K and a lap shear strength of 1500 PSI.
It is the object of the present invention to provide a durable and heat-resistant adhesive bond at the surface or in depth of a plate for densely ordered elements at any angle to the surface of the plate of the guided element.